How to deal with low haemoglobin during pregnancy?

Answered by: Dr Shirish Kumar | Haematologist, WHO, Geneva

Q:My wife is in 5th month of her pregnancy. I am really worried about her haemoglobin (Hb) count, which is 4.8 gms%. She has been anaemic for quite some time (almost 1 and half years), wherein her Hb was about 9 on an average. We have done several tests including bone marrow about one year ago and all results are normal. She is using iron tablets for last one month. We have been advised to take injections for iron supplements, which we have started. Also, recently we have done CBC test. The RBC count is 2.9 million cmm and packed cell volume is 17% other parameters are normal. Please advise.

A:Anaemia is inadequate level of haemoglobin appropriate for age & sex. The most common cause of anaemia in pregnancy is deficiency of iron (~85% cases) and folic acid. Even if a woman is not anaemic at the time of pregnancy, she may still develop anaemia as the pregnancy progresses due to increased demands of the developing baby. There are certain risk factors for women being anaemic and these include: poor nutrition, inadequate gap between pregnancies, persistent nausea or vomiting in early pregnancy and twin pregnancy.
The loss of iron (elemental) with each normal menses is around 12-15 mg. A normal diet must include 1.5-2 mg/day of elemental iron to compensate for menstrual losses alone. In pregnancy, 500 mg of additional iron is needed by the mother (to expand her red cell mass) while another 500 mg is needed for the baby and placental tissues. Thus, on an average, an additional 3 mg/day of elemental iron must be absorbed from dietary sources. The amount of iron absorbed by the body is only 10% of the total amount consumed, thus 30 mg/day needs to be consumed to meet the requirement.
An iron deficient mother can have premature labour, intrauterine growth retardation (poor development of baby), and severe anaemia due to normal blood loss during delivery and increased susceptibility to infection. The likelihood of postpartum transfusion may be reduced if a woman enters the birth period with a higher haemoglobin level.
Absorption of iron from food is influenced by multiple factors. One important factor is the form of the iron. Haeme iron, found in animal sources, is highly available for absorption in contrast to non-haeme iron found in vegetable sources. Vegetarians need more iron in their diets than non-vegetarians because the iron from plant foods is not as well absorbed as it is from animal foods. Vegetarians should choose several iron-rich plant foods daily. Grains, beans and lentils, vegetables (green-leafy ones, tomato, potato, green & red chillies etc), fruits, nuts and seeds are rich sources of non-haeme iron. The absorption of non-haeme iron can be improved when a source of haeme iron meat/fish/poultry is consumed in the same meal or iron absorption enhancing foods like fruits/fruit juices are consumed. But coffee/tea and calcium, if consumed along with a meal, impair iron absorption.
Treatment of most patients with iron deficiency is with oral iron therapy. The cheapest and most effective form is ferrous iron. The side effects experienced on taking iron tablet are proportional to the amount of iron available for absorption. The iron preparation you take should contain between 30-100 mg elemental iron. Avoid enteric-coated or prolonged-release preparations. The dose you take should be sufficient to provide between 150-200 mg elemental iron per day and the tablet may be taken 2 to 3 times a day about 1 hour before meals. Injectable form of iron is given to patients who are either unable to absorb oral iron or who have increasing anaemia despite adequate doses of oral iron. It is expensive and has greater side effects than oral iron preparations.